Are you high? Instagram (200 million users) uses PostgreSQL. PostgreSQL is web scale :)

The majority of POS terminals in the wild run Windows XP. This is unlikely to change anytime soon, so I have no idea how Windows XP's official retirement in a few days time will play out as none of the retailers I work with intend to change their tills. This isn't surprising (to people who support POS terminals), as we still see terminals running Windows NT4 (!!!!!!!).

Our advice to retailers is to always have their tills on a separate non-internet facing network. No one really does this though ....

It's handy having your an office suite on your tablet as it allows you to make quick edits on the go. No one is expecting you to write your thesis on a tablet, but for reviewing documents, writing comments and making small changes having Office on the iPad stupidly useful.

As for Office suites in general, I don't know what it's like where you are but in the UK you're almost guaranteed that to run into MS Office files in whatever job you do. There's no avoiding it even as a techie as your specifications and such are almost certainly written in Word.

Look, this is Slashdot. You're not going to find professional models here.

Obviously, with a question like that you're bound to get all sorts of answers. This is my 2 pence worth.